Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 23
Filter
1.
Article in English | WPRIM | ID: wpr-878357

ABSTRACT

Objective@#The aim of the present study was to evaluate the performance of the simultaneous detection of HIV-1 RNA, HIV-1 DNA, and HCV RNA using one dried blood spot (DBS) as an alternative sample to plasma.@*Method@#A total of 571 paired DBS/plasma samples were collected from men who have sex with men (MSM) and injection drug users (IDUs), and serological and molecular assays were performed. Using plasma results as the reference standard, the performance of DBS tests for HIV-1 RNA, HIV-1 DNA, and HCV RNA was evaluated. Pearson's correlation coefficients and Bland-Altman analysis were performed to assess the correlation and concordance between DBS and plasma.@*Results@#Among paired plasma/DBS samples with detectable HIV-1 RNA and HCV RNA, five samples (5/32) were not detectable in DBS, while measurable HIV-1 RNA levels were present in plasma (1.44 to 3.99 log @*Conclusion@#The performance of the simultaneous detection of HIV-1 RNA, HIV-1 DNA, and HCV RNA using one DBS was acceptable. DBS, as an alternative sample to plasma, may be a viable option for the simultaneous detection of HIV-1 RNA, HIV-1 DNA, and HCV RNA in resource-limited settings or for individuals living in areas that are difficult to access.


Subject(s)
DNA, Viral/analysis , Diagnostic Tests, Routine/methods , Dried Blood Spot Testing/methods , HIV Infections/diagnosis , HIV-1/isolation & purification , Hepacivirus/isolation & purification , Hepatitis C/diagnosis , RNA, Viral/analysis , Sensitivity and Specificity , Specimen Handling/methods , Syphilis/diagnosis , Treponema pallidum/isolation & purification
2.
Article in English | WPRIM | ID: wpr-875635

ABSTRACT

@#Introduction: Recognising the limitations of present dietary assessments method, recent attention had been drawn to image-based food record (IBFR) to assess dietary intake of the population. Thus, the present study aimed to compare nutrient intake assessed using IBFR with 24-hour diet recall (24DR) among nutrition and dietetics student. Method: There were 46 nutrition and dietetic undergraduates participated in the study, and information on the socio-demographic background and acceptability toward IBFR were obtained. Respondents were trained to complete one-day IBFR, and they were interviewed by researchers on the following day for their 24DR. Result: The mean age of respondents was 21.4±1.7 years old. The present study revealed that there were significantly higher protein and beta-carotene, but lower vitamin C reported by IBFR compared to 24DR. Medium to strong correlations were found between IBFR and 24DR for energy and nutrients intakes. The Bland-Altman analysis demonstrated a good level of agreement between IBFR and 24DR for energy and macronutrients (carbohydrates, protein and fat), respectively. The mean differences between IBFR and 24DR were -36 kcal for total daily energy intake, while mean differences of -12.24g, 0.79g, and 1.52g were reported for carbohydrates protein, and fat, respectively. Moderate level of agreement toward acceptability was demonstrated, and most of them (67.4%) preferred IBFR method. Conclusion: The present study revealed that IBFR showed a good level of agreement with 24DR in assessing nutrient intake. However, more extensive works should be considered to improve IBFR in assessing the energy and nutrients intake for the general population.

3.
Article in Chinese | WPRIM | ID: wpr-846362

ABSTRACT

Objective: To develop a new method for the determination of anti-oxidant activity of drugs by using the peroxidase activity of graphene nanoenzyme, and apply it for the determination of the anti-oxidant activity of the national medicine Achnatherum inebrians. Methods: The anti-oxidant activity of 18 batches of samples was measured after optimizing H2O2 concentration and reaction time. At the same time, the anti-oxidative activity was measured again using the DPPH method. The Bland-Altman and Passing-Bablok regression methods were used to compare the detection data of the two methods. Results: Using the nanoenzyme method, the inhibition rates of 18 batches of A. inebrians were between 37.28% and 71.58%, with an average of 50.87% and a median of 47.09%. Free radical scavenging rates of 18 batches of A. inebrians measured by the DPPH method were between 36.06% and 83.11%, with an average of 54.89% and a median of 50.83%. The statistical results showed that the measured values of nanoenzyme method and DPPH method were similar; There was a linear relationship between the two methods, and different methods can be transformed by Passing-Bablok regression method. Conclusion: The graphene nanoenzyme was successfully applied to the detection of anti-oxidant activity, and the anti-oxidant activity of A. inebrians was also found. The nanoenzyme method can avoid the problem of light sensitivity of the reagent, shorten the reaction time, reduce the amount of medicinal solution, and the results are consistent with the DPPH method, which is suitable for the determination of antioxidant activity.

4.
Medisan ; 23(5)sept.-oct. 2019. tab
Article in Spanish | LILACS, CUMED | ID: biblio-1091134

ABSTRACT

Introducción: El agua mantiene un rango normal en personas aparentemente sanas, el cual se altera ante la existencia de diversas enfermedades. Objetivo: Conocer cuánto se diferencian los valores de agua corporal total estimados por las ecuaciones de agua corporal total, de Kushner, de Deurenberg y de Heitman, con respecto a los obtenidos clínicamente por el método de impedancia bioeléctrica a 50 kHz. Métodos: Se realizó un estudio descriptivo y transversal, de abril a diciembre del 2018, en 62 individuos: 31 adultos aparentemente sanos y 31 niños y adolescentes con diferentes enfermedades, ingresados en el Hospital Infantil Docente Sur Dr. Antonio María Béguez César de Santiago de Cuba (24 en el Servicio de Misceláneas y 7 en el de Oncopediatría). El agua corporal total y los parámetros bioeléctricos se estimaron con el analizador de impedancia bioeléctrica Bodystat® 1500-MDD, a 50 kHz, por el método tetrapolar ipsilateral derecho. Se utilizó el criterio de Bland-Altman, para un 95 % de confianza, a fin de conocer si las ecuaciones de Kushner, de Deurenberg y de Heitman podían sustituir a la ecuación de referencia. Resultados: Las ecuaciones de agua corporal total, de Kushner y de Deurenberg no mostraron diferencias significativas respecto a la ecuación de referencia, mientras que la ecuación de Heitman sí presentó diferencias significativas en relación con el resto de las ecuaciones. El método de Bland-Altman demostró que la ecuación de Kushner posee mayor concordancia con la ecuación de referencia. Conclusiones: La ecuación de Kushner es la de mayor exactitud para la estimación del agua corporal total en personas sanas y en las afectadas por entidades clínicas.


Introduction: The water maintains a normal range in apparently healthy people, which changes with the existence of diverse diseases. Objective: To know how the values of total body water estimated by Kushner, Deurenberg and Heitman equations of total body water, differ regarding those obtained clinically by the method of bioelectric impedance at 50 kHz. Methods: A descriptive and cross-sectional study was carried out, from April to December, 2018, in 62 individuals: 31 apparently healthy adults and 31 children and adolescents with different diseases, admitted to "Dr. Antonio María Béguez César" Southern Teaching Children Hospital in Santiago de Cuba (24 in the Miscellaneous Service and 7 in Oncopediatrics Service). The total body water and the bioelectric parameters were considered with the analyzer of bioelectric impedance Bodystat® 1500-MDD, at 50 kHz, for the right ipsilateral tetrapolar method. The approach of Bland-Altman was used, for 95% of confidence in order to know if Kushner, Deurenberg and Heitman equations could substitute the reference equation. Results: Kushner and Deurenberg equations of total body water didn't show significant differences regarding the reference equation, while Heitman equation presented significant differences related to the rest of the equations. The Bland-Altman method demonstrated that the equation of Kushner has higher concordance with the reference equation. Conclusions: Kushner equation has the highest accuracy for the estimate of total body water in healthy people and in those affected by diseases.


Subject(s)
Body Water , Electric Impedance
5.
Acta Anatomica Sinica ; (6): 627-632, 2019.
Article in Chinese | WPRIM | ID: wpr-844612

ABSTRACT

Objective To observe the difference of the human body surface area (BSA) formula based on three-dimensional measurement in practical application. Methods The data of 1249 college students (639 males, 610 females) from physical health examination in 2018 were selected. Using the one-way factorial analysis of variance (ANOVA), correlation analysis and Bland-Altman comparative analysis, comparisons between the BSA values using four BSA calculation formulas based on three-dimensional measurement and with the traditional formula measurement by Yongmei Hu's were made as well. Results There were significant statistical differenes between the BSA values of the formulas (P 0. 985) were also rather high. Results from Hu Yong-mei's formula were higher than the other four 3D formulas in both genders, with the BSA of males 7. 32%-12. 11% higher than the mean while female BSA values were 5. 53%-11.72% above the average. It has been shown from the Bland-Altman analysis that the formula from ChiYuang Yu had the highest consistency score (95 % CI 1.021-1.034) among the selected four 3D measurement formulas. Conclusion Within the four BSA formulas based on 3D measurement principle, ChiYuang Yu's formula is relatively more suitable to estimate the BSA values of both Chinese males and females.

6.
Article in Chinese | WPRIM | ID: wpr-775547

ABSTRACT

The article aims to discuss the feasibility of using respiratory sounds to monitor respiratory rate. The average power of respiratory sounds was created firstly, the autocorrelation algorithm was used to calculate the respiratory cycle. The respiratory cycle of nasal flow pressure signal was calculated simultaneously, and the result was taken as a reference standard, then, two groups of respiratory cycle data were analyzed by correlation analysis and Bland-Altman analysis. The respiratory rate is relatively stable, using respiratory sounds monitor respiratory rate is feasible, the respiratory rate changes obviously, the existing methods and algorithm using respiratory sounds are temporarily unable to accurately reflect the changes of respiratory rate, further research is needed.


Subject(s)
Algorithms , Humans , Monitoring, Physiologic , Respiratory Rate , Respiratory Sounds
7.
Journal of Medical Postgraduates ; (12): 118-123, 2018.
Article in Chinese | WPRIM | ID: wpr-700786

ABSTRACT

With the promotion and application in medicine and sanitary fields,the reporting quality of Bland-Altman agreement evaluation is worrying.This study aimed at developing a set of reporting standards for Bland-Altman agreement evaluation as the guidance for proper application to improve the reporting quality.A research group was launched to work on reporting standards for Bland-Altman agreement evaluation,and all the requirements for personnel on various levels were made clear.Early in the study,we carried out articles reviews,regular meetings,expert consultations,literary evaluation,item integration and extraction.Then,we invited a multi-disciplinary panel of experts to improve overall design,evaluate reporting items and form the first draft by brainstorming method.Multiple rounds of expert consultations were also conducted with reference to Delphi method to integrate expert advice and form the basic framework of reporting items.Finally,through the thorough analysis and demonstration,we proposed the reporting items for the agreement evaluation of Bland-Altman method (RiBAM) as the recommended report.A list of recommended items called RiBAM was formed,which consisted of 17 first-level items and 23 secondary-level items.RiBAM is more comprehensive and systematic as an important reference for improving the quality of reports by avoiding the omission of reporting contents and achieving the clarity,integrity and transparency of the report.RiBAM recommended items can be a guide for authors in reporting Bland-Altman agreement evaluation as well as a basic reference for journal editors,peer reviewers and readers.

8.
Article in Chinese | WPRIM | ID: wpr-615864

ABSTRACT

Objective To discuss the agreement between pulse pressure variation of radial artery and pulse pressure variation of dorsal pedalartery in neurosurgery.Methods Twenty-five patients undergoing selective craniotomy under general anesthesia were enrolled.The following data were monitored and recorded respectively after tracheal intubation general anesthesia under different time:radial artery pulse pressure variability (PPV1) and dorsalis pedis pulse pressure variation (PPV2).Tidal volume was set to 8 ml/kg.Bland-Altman plots were created to assess agreement between PPV1 and PPV2.Results The mean differences and the limits of agreement between PPV1 and PPV2 are 20 min after induction of anesthesia 0.5% (-1.9%-2.8%), boneless flap instantly-0.5% (-3.8%-2.9%), Cut the dura mater instantly-0.1% (-3.2%-3.0%), and bone flap 0.1% (-2.4%-2.6%).Conclusion Dorsal pedal artery pulse pressure variation in neurosurgery craniotomy has certain guiding significance to the monitoring and management.

9.
Ciênc. rural ; 46(11): 2049-2054, Nov. 2016. tab, graf
Article in English | LILACS-Express | LILACS | ID: lil-796075

ABSTRACT

ABSTRACT: Proper monitoring of cardiac index (CI) in critically ill patients requires accurate and minimally invasive methods. The aim of this study was to compare the CI values obtained by thermodilution or echocardiography using different methods in dogs in different hemodynamic states. Nine dogs weighing 19.6±1.3kg were anesthetized with isoflurane at 1.4V% (Baseline) and subjected to mechanical ventilation (MV),a hypodynamic state (Hypo) with isoflurane at 3.5V% and hyperdynamic state (hyper) with dobutamine infusion at 5μgkg-1min-1. CI analysis was performed by thermodilution (TD) and using the modified Simpson's method, aortic velocity-time integral (A-VTI) method and pulmonary VTI (P-VTI) method. We performed Pearson's correlation and Bland-Altman analysis. The CI values (Lm-2min-1) of the animals in the Baseline, MV, Hypo and Hyper states were 4.3±1, 3.6±0.7, 2.9±0.66 and 6.1±2, for TD; 2.8±0.7, 2.4±0.3, 1.7±0.7 and 4.4±1.2, for Simpson's method; 3.4±0.9, 3.1±0.7, 2.6±3.4, 6.1±1.8 for A-VTI; and 3.6±0.8, 3.6±0.8, 2.7±0.6 and 6.2±1.5, for P-VTI. The CI values using Simpson's method were lower than those obtained by TD in all states, and it was observed a significant correlation in the Hypo (r=0.89) and Hyper (r=0.76) groups. In addition,the percent error in the Hypo group using Simpson's method was 26% relative to TD, which allowed for the identification of the different hemodynamic states. With respect to the other methods and states, there was no agreement or correlation between the methods and TD. We concluded that none of the tested echocardiography methods exhibited acceptable agreement with thermodilution at different hemodynamic states.


RESUMO: A adequada monitoração do índice cardíaco (IC) em pacientes críticos requer métodos acurados e minimamente invasivos. O objetivo deste estudo foi comparar o IC obtido por termodiluição ou ecocardiografia em cães sob alterações hemodinâmicas. Utilizaram-se nove cães pesando 19,6±1,3kg, os quais foram anestesiados com isofluoranoa1,4V% (Basal) e submetidos à ventilação mecânica (VM) e estados hipodinâmico (Hipo) com isofluoranoa3,5V% e hiperdinâmico (Hiper), com dobutaminaa5µgkg-1min-1. O IC foi obtido por termodiluição (TD) e pelos métodos ecocardiográficos de Simpson modificado, e pela velocidade em tempo integral (VTI) nas valvas aórtica (VTI-A) e pulmonar (VTI-P). Realizou-se a análise de correlação de Pearson e de concordância de Bland-Altman. O IC (Lm-2min-1) nas fases Basal, VM, Hipo e Hiper foi de 4,3±1, 3,6±0,7, 2,9±0,66 e 6,1±2 para TD; 2,8 ±0,7, 2,4±0,3, 1,7±0,7 e 4,4±1,2 para Simpson; 3,4±0,9, 3,1 ±0,7, 2,6±3,4, 6,1±1,8 para VTI-A e 3,6±0,8, 3,6±0,8, 2,7±0,6 e 6,2±1,5 para VTI-P. O método de Simpson foi menor que a TD em todas as fases, mas com correlação significativa nos estados Hipo (r=0,89) e Hiper (r=0,76) e percentagem de erro de 26% no Hipo em relação à TD, identificando os diferentes estados hemodinâmicos. Nos demais, não houve concordância ou correlação com a TD. Conclui-se que nenhum dos métodos testados apresentou concordância aceitável com a termodiluição nos diferentes estados hemodinâmicos.

11.
Indian J Ophthalmol ; 2016 Feb; 64(2): 132-135
Article in English | IMSEAR | ID: sea-179127

ABSTRACT

Context: Precise intraocular pressure (IOP) measurement is important in glaucoma practise. Various instruments are available today to accurately measure IOP. Thus, the question arises about which instrument to use and whether all of them can be used interchangeably. Aims: To assess the agreement between noncontact tonometer (NCT), rebound tonometer (RBT), Goldmann applanation tonometer (GAT), and dynamic contour tonometer (DCT) in measuring IOP. Subjects and Methods: 499 eyes of 250 patients were evaluated during a period of 24 months from September 2010 to August 2012 and measurement of IOP by NCT, RBT, GAT, and DCT was done in the given sequence. The agreement was assessed by use of the Bland–Altman plot keeping GAT as a gold standard technique. Results: The mean IOP value of NCT, RBT, GAT, and DCT was 15.9 ± 5.5, 15.9 ± 5.8, 15.9 ± 4.9, and 16.0 ± 4.7 mm of Hg, respectively. The limits of agreement of GAT with DCT, NCT, and RBT were found to be +5.4 to −5.2, −4.7 to +4.6, and −5.2 to +5.1 mm of Hg, respectively. Conclusions: A positive and strong correlation was found between newer tonometers and GAT, but the limit of agreement was clinically unacceptable. The use of a single tonometer should be practised at a glaucoma clinic for a patient at each follow‑up.

12.
Article in Chinese | WPRIM | ID: wpr-501982

ABSTRACT

Objective To evaluate the accuracy of prediction equations in calculating energy expenditure in elderly patients with type 2 diabetes mellitus (T2DM).Methods In 75 elderly T2DM patients hospitalized in our hospital between August 2014 and August 2015,the resting energy expenditure (REE)measured with indirect calorimetry was compared with those calculated with six different prediction equations.Statistical analysis was performed with paired t-test,the percentage of individual coincidence,and BlandAltman method.Results The measured REE of the patients was (1 513.2 ± 240.6) kcal/d.There were statistically significant differences between the measured REE and the values predicted with Harris-Benedict,Owen,Mifflin,and Liu equations (all P < 0.05),while no statistically significant differences were observed between the measured REE and the values predicted with FAO/WHO/UNU and Schofield equations (both P >0.05).FAO/WHO/UNU equation showed the smallest average difference from the measured value (-18.9 kcal/d),but the 95% consistency limit (-363.3 kcal/d,325.5 kcal/d) was still beyond the acceptable clinical range.Conclusion The accuracy of prediction equations in estimating REE in elderly patients with T2DM may be dissatisfactory.

13.
Arq. bras. med. vet. zootec ; 67(5): 1263-1271, tab, graf
Article in Portuguese | LILACS | ID: lil-764460

ABSTRACT

A monitoração do estado hemodinâmico visa ao equilíbrio entre a oferta e a demanda de oxigênio tecidual. O objetivo deste estudo foi avaliar a utilização da calorimetria indireta (CI) frente à termodiluição (TD) em cães sob diferentes estados hemodinâmicos. Utilizaram-se nove cães pesando 19,6±1,3kg, os quais foram anestesiados com isofluorano a 1,4V% (Basal), submetidos à ventilação mecânica (VM) e estados hipodinâmico (Hipo), com isofluorano a 3,5V%, e hiperdinâmico (Hiper), com dobutamina a 5µg/kg/min. Utilizou-se um cateter de Swan-Ganz para aferição do índice cardíaco (IC) por TD, cálculo do consumo de oxigênio pelo método de Fick (VO2Fick) e para coleta de sangue venoso central e misto. Com a CI, obtiveram-se os valores de consumo de oxigênio (VO2), produção de CO2(VCO2) e expirado de CO2 (EtCO2). Para a determinação do IC por CI, utilizou-se o princípio de Fick com os valores de VO2 e os sangues arteriais e venosos misto (Fickmix) ou central (Fickvc), e pela relação dos valores de VCO2 e EtCO2(FickCO2). A análise estatística compreendeu os testes de Dunnet, para diferença entre as fases, e Tukey, para diferenças entre os métodos (P≤0,05). Foram realizadas as análises de correlação de Pearson e de concordância de Bland-Altman. A CI forneceu valores de VO230 a 40% maiores que VO2Fick, mas identificou a redução no VO2 após a VM e Hipo, o que não ocorreu com VO2Fick. Os valores de VCO2diminuíram nas fases VM e Hipo. Houve redução do IC na fase Hipo com todos os métodos e aumento na fase Hiper com TD e Fickvc. Os valores de IC pelos métodos de Fickmixe Fickvc foram maiores que TD em todos os momentos, e FickCO2foi menor que TD na fase Hiper. Nenhum dos métodos apresentou concordância e correlação com a TD. Conclui-se que a CI pode ser utilizada na mensuração do VO2 e VCO2 de cães sob diferentes estados hemodinâmicos. Contudo, embora seja possível a identificação dos diferentes estados hemodinâmicos, os valores de IC não podem ser comparados à termodiluição.


Monitoring the hemodynamic state seeks a balance between the supply and demand of oxygen by tissues. The aim of this study was to evaluate the use of indirect calorimetry (IC) compared to thermodilution (TD) in dogs under different hemodynamic states. Nine dogs weighing 19.6±1.3kg were anesthetized with isoflurane at 1.4 V% (Baseline) and subjected to mechanical ventilation (MV), a hypodynamic state (Hypo) with isoflurane at 3.5V% and hyperdynamic state (Hyper) with dobutamine infusion at 5μg/kg/min. We used a Swan-Ganz catheter for measurement of cardiac index (CI) by TD, calculation of oxygen consumption by Fick's method (VO2Fick) and to collect central and mixed venous blood. With the IC we obtained oxygen consumption (VO2), CO2 production (VCO2) and end tidal CO2(EtCO2). For the determination of CI by IC we used the Fick's principle with VO2values, and arterial and mixed venous blood (Fickmix)or arterial and central venous blood (Fickvc); and by the ratio of the values of VCO2 and EtCO2(FickCO2). We performed the statistical analysis by Dunnet tests, for the difference between the states, and Tukey for differences between methods (P≤0.05). Pearson correlation and Bland-Altman analysis was performed for correlation and agreement analysis. IC provided VO2values 30 to 40% higher than the VO2Fick but identified the reduction in VO2after VM and Hypo, which did not occur with VO2Fick. The VCO2 values decreased in VM and Hypo. CI values decreased in Hypo with all methods and increase in Hyper with TD and Fickvc. The CI values for Fickmix and Fickvc were greater than TD at all times and FickCO2 was lower than TD in the Hyper. None of the methods presented agreement and correlation with TD. Thus, indirect calorimetry can be used to measure the VO2 and VCO2 in dogs in different hemodynamic states. However, although it is possible to identify the hemodynamic status, cardiac index values cannot be compared to thermodilution.


Subject(s)
Animals , Dogs , Calorimetry, Indirect , Calorimetry, Indirect/veterinary , Hemodynamics , Cardiac Output , Oxygen Consumption
14.
Article in Chinese | WPRIM | ID: wpr-471092

ABSTRACT

Objective To establish a practicable and easily mastered emergency department overcrowding (EDO) assessment system suitable for domestic ED setting by determining the validity and usefulness of the national emergency department over-crowding study (NEDOCS) tool in a 2000-bed tertiary care academic institution in China in comparison with visual analogue scale (VAS) in order to address the worldwide grave concern of EDO.Methods In a period of 6 months,data of subjective and objective EDO assessed simultaneously three times a day (1:00,9:00,17:00) were collected.The data were analyzed by using Bland-altmann method and Kappa test to determine the coincidence between VAS and NEDOCS assessments.Results The VAS-p value evaluated by physicians was significantly lower than VAS-n value evaluated by nurses [(6.49 ± 1.82) vs.(7.12 ± 1.78),P < 0.01].The reliability analysis showed that Kappa value was as low as 0.112 (P <0.01) suggesting there was a great discrepancy between VAS-p value and VAS-n value.VAS-m (average value of VAS-p and VAS-n) was taken for comparing different evaluation systems.The significant correlation was found between the VAS-m and NEDOCS (r =0.7l4,P <0.01).However,the Bland-Altman plot showed the 95% limit of coincidence was in an extensive range (-32.47 to 71.42) suggesting discrepancy existed between two methods.Conclusions The present study suggested there was a significant discrepancy between the two subjective assessments of ED crowding (VAS-p vs.VAS-n).There might be a fatal flaw existed in the assumptions of the original VAS method for EDO measurement.Using the Bland-Altman plot analysis,the results showed that NEDOCS did not authentically reflect the staff' s sense of overcrowding in the ED.It is very important and urgent to establish an objective and effective EDO evaluation system for ED management.

15.
Journal of Medical Postgraduates ; (12): 1107-1111, 2015.
Article in Chinese | WPRIM | ID: wpr-481215

ABSTRACT

The Bland-Altman method has been widely used for consistency evaluation in the field of medicine .However, fre-quent errors in the application of the method seriously affect the quality of researches .This review focuses on the studies of the Bland-Altman method , the status quo and common problems in its application , and standards for related reports .

16.
Rev. bras. ativ. fís. saúde ; 19(1): 64-73, jan. 2014. tab
Article in English | LILACS | ID: biblio-124

ABSTRACT

This study aimed to create an equation to predict peak oxygen uptake from data of the 6-minute walk/run test and demographic and anthropometric variables in adolescents. The results of the 6-minute walk/run (6WRT), peak oxygen uptake, height, body weight and body mass index (BMI) in 125 adolescents age 10 to 14, of which 66 were female, were assessed. They were divided into a validation and a cross-validation group. A linear regression analysis was conducted to assess the associations between the independent variables 6WRT, age, gender, anthropometric measurements and the dependent variable peak oxygen uptake in the validation group. The Bland-Altman method was used to test agreement between measured and estimated values. It was found that the best model to predict peak oxygen uptake included the 6-minute walk/run test, BMI, and gender. These variables presented a multiple correlation coefficient of 0.77 and a standard error of estimate of 3.99 [(mL/kg)/min]. The accuracy of the model was tested by applying the equation created in the validation group to the cross-validation group and total sample. The Bland-Altman method results did not indicate any systematic bias or heteroscedasticity in both the validation and cross-validation groups. In conclusion, our multiple regression equation [peak oxygen uptake = 41.946 + 0.022(6WRT) ­ 0.875(BMI) + 2.107(gender)] is adequate for predicting peak oxygen uptake in adolescents age 10 to 14.


Este estudo objetivou criar uma equação para a predição do consumo de oxigênio de pico em adolescentes a partir do teste de corrida/caminhada de 6 minutos, variáveis demográficas e antropométricas. Os resultados do teste de corrida/caminha de 6 minutos (6-min), consumo de oxigênio de pico, estatura, massa corporal e índice de massa corporal (IMC) de 125 adolescentes de 10 a 14 anos de idade (66 moças) foram avaliados. A amostra foi dividida em um grupo validação e um grupo validação cruzada. A análise de regressão linear múltipla foi utilizada para analisar as associações entre o 6-min, idade, sexo e medidas antropométricas (variáveis independentes) e o consumo de oxigênio de pico (variável dependente) no grupo validação. O diagrama de Bland-Altman foi utilizado para testar a concordância entre os valores medidos e estimados. O melhor modelo encontrado para predizer o consumo de oxigênio de pico incluiu o 6-min, o IMC e o sexo. Estas variáveis apresentaram um coeficiente de correlação múltipla de 0,77 e um erro padrão de estimativa de 3,99 [(mL/kg)/min]. A acurácia do modelo foi testada aplicando a equação criada no grupo validação no grupo validação cruzada e em toda a amostra. Os resultados do diagrama de Bland-Altman não indicaram erro sistemático e heteroscedasticidade tanto no grupo validação quanto no grupo validação cruzada. Em conclusão, a equação proposta [consumo de oxigênio de pico = 41,946 + 0,022(6-min) ­ 0,875(IMC) + 2.107(sexo) é adequada para predição do consumo de oxigênio de pico em adolescentes de 10 a 14 anos de idade.


Subject(s)
Humans , Male , Female , Adolescent , Adolescent , Heart Function Tests
17.
Medisan ; 17(9): 4054-4063, set. 2013.
Article in Spanish | LILACS-Express | LILACS | ID: lil-687227

ABSTRACT

Se efectuó un estudio comparativo de 2 analizadores comerciales de bioimpedancia eléctrica corporal (Bodystat® 1500-MDD y BioScan®98) en el Servicio de Oncopediatría del Hospital Infantil Sur de Santiago de Cuba, desde septiembre hasta octubre del 2009, para lo cual se realizó una simulación in vitro con los calibradores de cada equipo y un estudio in vivo de 32 adultos aparentemente sanos y 32 niños con diferentes afecciones. La resistencia eléctrica y la reactancia capacitiva se estimaron con ambos analizadores; además, se calcularon el módulo de impedancia y el ángulo de fase. La prueba t-student de 2 medias para muestras apareadas y el método de Bland-Altman fueron los criterios estadísticos usados. No existieron diferencias significativas entre ambos analizadores al introducir los factores de corrección para la resistencia eléctrica y la reactancia capacitiva; por tanto, es posible usarlos indistintamente para caracterizar bioeléctricamente a los individuos aparentemente sanos y pacientes con diferentes enfermedades.


A controlled trial with 2 body electrical impedance commercial analyzers was carried out (Bodystat® 1500-MDD and BioScan®98) at the Pediatric Oncology Department of the Southern Children Hospital in Santiago de Cuba, from September to October 2009, for which an in vitro simulation with gauges of each device and an in vivo study in 32 apparently healthy adults and 32 children with different conditions were conducted. Electrical resistance and capacitive reactance were estimated with both analyzers, and impedance module and phase angle were also calculated. The two-means Student's t test for paired samples and the Bland-Altman method were used as statistical criteria. There were not significant differences between the two analyzers by introducing correction factors for electrical resistance and capacitive reactance; therefore, it is possible to use either to characterize bioelectrically apparently healthy individuals and patients with different conditions.

18.
Br J Med Med Res ; 2012 Oct-Dec; 2(4): 536-552
Article in English | IMSEAR | ID: sea-162754

ABSTRACT

Aims: In epidemiological studies exposure assessment based on questionnaires is the most cost-effective method. A question about lifetime exposure to occupational physical activity (OPA) was used in a population-based survey (part of the Copenhagen Aging and Midlife Biobank, CAMB). The aim of the study was to validate this question through a three-step process. Methodology: Firstly, the response process was studied by cognitive interviewing of 7 persons. Secondly, 64 persons participated in semi-structured interviews about their work-life, and expert judgments of exposure to OPA were compared with questionnaire-data. Exposure was 20 years of work in one of four categories of OPA: sedentary, standing and walking, moderate or high OPA. Kappa values were calculated for agreement and interpreted according to Landis and Koch’s criteria. Agreement was visualized in Bland-Altman plots. Thirdly, intra- and inter-rater reliability of expert judgments was tested. Results: Response process: The question had a complicated instruction, and the respondents found it hard to remember, categorize, and summate exposures. Semi-structured interviews: Kappa value for exposure to sedentary work was ‘substantial’ (0.71) but ‘fair’ for the other categories of OPA (0.27-0.29). Agreement between questionnaire and interview was higher in sedentary jobs and jobs with high OPA. Intra-rater reliability of expert judgments was ‘substantial’ or ‘moderate’ (0.60-0.71). Inter-rater reliability was high in sedentary jobs but lower in the more active jobs. Conclusion: Self-reports of lifetime exposure to sedentary work are valid in the CAMB cohort, whereas the validity of self-reports of exposure to high levels of occupational physical activity (OPA) are questionable. Thorough pre-testing of questions about lifetime OPA is recommended.

19.
Article in Portuguese | LILACS | ID: lil-552661

ABSTRACT

Quando se pretende avaliar a concordância entre dois métodos que deveriam medir a mesma quantidade, são utilizadas análises que nem sempre estão corretas. É importante que seja evitado o uso da correlação nestas situações e que a metodologia seja utilizada de forma adequada, incluindo os limites de concordância e seus intervalos de confiança, além de comentar se os limites encontrados são diferenças aceitáveis do ponto de vista clínico. A proposta do presente artigo é apresentar um método bastante simples que já é utilizado há bastante tempo, que é a análise de concordância entre métodos de Bland-Altman, salientando alguns problemas detectados na sua utilização. Para isto, foi feita uma simulação de três diferentes situações, com comentários e soluções. O programa R, por ser livre e ter incorporado comandos para a análise de Bland-Altman, foi utilizado para a análise dos resultados.


When the intention is to evaluate the agreement between two methods that would measure the same quantity, the analyses used are not always correct. It is important to avoid the use of correlation in these situations and to properly use the methodology, including the analysis of limits of agreement and confidence intervals, and to comment on whether the limits are acceptable differences from a clinical point of view. The purpose of this paper is to present a simple method which has been already in use for some time, the Bland-Altman analysis of agreement between methods, pointing out some problems encountered with its use. For this, a simulation of three different situations was performed, with comments and solutions. The R program was used to analyze the results, because it’s free and has available commands of the Bland-Altman analysis.


Subject(s)
Humans , Methodology as a Subject , Laboratory and Fieldwork Analytical Methods/analysis , Laboratory and Fieldwork Analytical Methods/statistics & numerical data , Laboratory and Fieldwork Analytical Methods/ethics , Laboratory and Fieldwork Analytical Methods/methods , Statistics, Nonparametric
20.
Arq. bras. endocrinol. metab ; 52(6): 1050-1055, ago. 2008. ilus
Article in Portuguese | LILACS | ID: lil-492937

ABSTRACT

A dosagem de testosterona sérica, total ou fração livre, é metodologia de alto valor diagnóstico e encontra-se disponível na maioria dos laboratórios clínicos. Esta disponibilidade foi possível pelo desenvolvimento de metodologias simples e diretas, adaptáveis a plataformas de dosagem automatizada. Uma série de publicações recentes tem alertado quanto às limitações destas metodologias, em especial em amostras com baixas concentrações, como mulheres e crianças. Neste trabalho serão apresentados os resultados do emprego de uma metodologia de referência, fundamentada em cromatografia líquida de alta performance e espectrometria de massa em tandem (HPLC/MS-MS), e sua comparação com uma dosagem de rotina (ensaio eletroquimioluminescente - ECLIA). Os métodos são comparados tanto na dosagem de testosterona total (n = 213) quanto na determinação de testosterona livre calculada com base na determinação da testosterona total e da proteína carregadora de hormônios sexuais (SHBG) (n = 135). Os valores obtidos com o ECLIA são significativamente mais elevados, sendo a dispersão mais nítida em soros com baixas concentrações. Tal fenômeno fica mais claro quando apresentado na forma de gráficos de Bland-Altman. Neste trabalho são discutidas as dificuldades de implementação de uma metodologia de referência, como a apresentada, e a convivência com as metodologias de rotina, bem como a literatura recente sobre o assunto.


Serum testosterone in its total or free form, is a highly valuable diagnostic test and is available in the great majority of clinical laboratories. This reality was possible due to the development of simple and direct assays, adaptable to large automatic systems. Recent publications have called attention to the limitations of these simplified methodologies, mainly in samples with low concentration, as women and children. In this paper we present results obtained using a reference method based on high performance liquid chromatography and tandem mass spectrometry (HPLC/MS-MS) and its comparison with those obtained with a commercial routine immunoassay (electrochemiluminescent assay, ECLIA). Methods were compared in total testosterone measurement (n = 213), as well as in free testosterone evaluation based on calculation inclu-ding sex hormone-binding protein (SHBG) levels (n = 135). Values obtained with ECLIA were significantly higher, with more marked dispersion in low concentration. This phenomenon is clearer when presented as a Bland-Altman plot. Difficulties in the implementation of reference methods as the one presented are discussed, as well as the necessity of caution in the interpretation of values obtained with routine assays, a matter of several publications in recent literature.


Subject(s)
Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Young Adult , Chromatography, High Pressure Liquid/methods , Luminescent Measurements , Tandem Mass Spectrometry/methods , Testosterone/blood , Data Interpretation, Statistical , Electrochemistry , Reference Values , Sensitivity and Specificity , Sex Hormone-Binding Globulin/analysis , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL